An early-responding SWAT team was allegedly told to stand down by supervisors during Monday’s deadly Washington Navy Yard shooting that left 12 dead, according to the BBC.

The board of the U.S. Capitol Police department is investigating orders for the Containment and Emergency Response Team (Cert) team to leave the scene of the mass shooting.

“I don’t think it’s a far stretch to say that some lives may have been save if we were allowed to intervene,” a department source told police.

The tactical team was reportedly near the Navy Yard when 34-year-old Aaron Alexis opened fire in Building 197 on the yard. They arrived quickly to assist Metropolitan police after receiving news of the active shooting around 8:20 a.m.

When they contacted supervisors, they were commanded to leave the scene. The four-man team were reportedly the only officers on the scene with long guns.

Alexis was killed around 9 a.m.

Candice Miller (R-Mich.), chairwoman of the House Administration, told Fox News that she was told that “there is currently an active investigation into the allegation.”

However, the Metropolitan Police Department denied the allegations to the BBC.